Is Diabetes related to HT?

In a word, yes.

Here's a fairly good review of the research on HT side effects. If you scroll half way down you will see what it says about diabetes.

onlinelibrary.wiley.com/doi/10.1002/cncr.24283/full

It says, in part:

Incident diabetes appears to be a side effect of ADT. The studies listed in Table 3 by Keating et al36 and Lage et al37 reported significantly increased risks of incident diabetes between 36% and 49%. This finding is not surprising given the results of previously published literature, which reported significant elevations of hyperglycemia and increased insulin resistance in men who underwent ADT as well as worsened glycemic control in diabetic men who underwent ADT.

Now that you are back off the HT you might be able to adjust your diet to reverse many of the effects. Something to ask you doctor about when you see him.

You might ask your doctor about whether a low-carbohydrate Mediterranean diet would work for you. It features lots of lettuce, true, but you can slather it with olive oil and eat it with lots of fish, fowl, and nuts. It can be pretty tasty.

I am now on 500 mg of metiphorme (sp)
Given up most carbs so we will see where I end up.
Still complete ED.